I was recently told that a new 55mm f/1.3 lens would be announced on March 26, 2013. This is the first time I have ever seen an announcement date called this far off. Although, I tend to believe something is probably going to happen in March of 2013. I find it odd that Canon won’t be doing the announced firmware for the 5D Mark III until April 2013, I’m not sure if that’s tied to other new products coming.

As for the lens, it wasn’t specified if it was EF or EF-M mount, I have just assumed it would be EF-M. For arguments sake, that would give an approximate field of view of 90mm f/1.3. A nice portrait lens for the new system.

"For arguments sake, that would give an approximate field of view of 90mm f/1.3. A nice portrait lens for the new system."

Just to clarify, it would be the approximate equivalent of a 90mm f/2.0 FF lens. You have to take the crop factor into account when comparing apertures as well as focal lengths.

You are right if yuo think about Dept of field, but in term of shutter speed the aperture it is still faster (must admit that with crop you have to use faster speed to avoid shake).Diego

Actually, when you take noise into effect, you also have to decrease the effective aperture to get a valid comparison with a larger format. I can't do the math, but it's also roughly a stop.

That is, f/1.3 @ ISO 100 on APS-C really is comparable to f/2.0 @ ISO 200 on full frame. And f/1.3 @ ISO 100 on full frame would be comparable to f/1.0 @ ISO 50 on APS-C. (Roughly, with rounding, etc., etc., etc.)

"For arguments sake, that would give an approximate field of view of 90mm f/1.3. A nice portrait lens for the new system."

Just to clarify, it would be the approximate equivalent of a 90mm f/2.0 FF lens. You have to take the crop factor into account when comparing apertures as well as focal lengths.

You are right if yuo think about Dept of field, but in term of shutter speed the aperture it is still faster (must admit that with crop you have to use faster speed to avoid shake).Diego

Actually, when you take noise into effect, you also have to decrease the effective aperture to get a valid comparison with a larger format. I can't do the math, but it's also roughly a stop.

That is, f/1.3 @ ISO 100 on APS-C really is comparable to f/2.0 @ ISO 200 on full frame. And f/1.3 @ ISO 100 on full frame would be comparable to f/1.0 @ ISO 50 on APS-C. (Roughly, with rounding, etc., etc., etc.)

b&

This bunch is much, much smarter than the guys over on Model Mayhem. Or, at least, better at reading comprehension.

Actually, when you take noise into effect, you also have to decrease the effective aperture to get a valid comparison with a larger format. I can't do the math, but it's also roughly a stop.

That is, f/1.3 @ ISO 100 on APS-C really is comparable to f/2.0 @ ISO 200 on full frame. And f/1.3 @ ISO 100 on full frame would be comparable to f/1.0 @ ISO 50 on APS-C. (Roughly, with rounding, etc., etc., etc.)

b&

So the noise from a EOS D30 (2001) is one stop behind the 1D X? I don't think so. Everyone understands noise is in constant flux throughout models, formats, etc. So I think it is fair to leave noise out of the equation as it is not a constant like shutter speed and aperture. Given two models of camera it is fair to make a comparison on the level of noise and how many stops of advantage one has over another, but to make a blanket statement is not fair.

Here's the math:

FF crop factor: 1APS-C crop factor: 1.6

f/1.3 * 1.6 = f/2.0 equivalent 90mm (for background blur of 55mm f/1.3 lens in FF terms)f/1.3 / 1.6 = f/0.83 equivalent (although your point is misleading as an EF-M lens has a flange distance too short for a FF DSLR - and most likely an image circle to small to cover a full frame sensor)

All you need to do is multiply the aperture (or focal length) by the crop factor to go up in formats, and divide to go down.